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1

Theoretical and Practical Aspects of Pneumatic Powder Injection into Liquid Alloys with a Non-Submerged Lance

Jezierski J., Janerka K., Stawarz M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 2

731--734

EN

The method of powder injection into molten metal has been widely known since tens of years and successfully utilized in various metallurgical processes. The most common is a solution with injection lance submerged under the liquid alloy surface, because it is easier apart from some of disadvantages of this approach. In this paper the authors’ complex experiments on the pneumatic injection process with non-submerged lance have been presented. The new approach on jet cone angle importance and its influence on the efficiency of the injection process has been shown. The issue of the effective jet radius that was proposed by former scientists as well as computer modelling and injection experiments recorded with high speed camera have been presented. The final comparison of the typical injection lance and developed by authors new lance with flange was presented, too. The benefits of use of a new one for the treatment of small liquid alloy volume (e.g. inoculation or alloys addition introduction) have been pointed.

PL

Technologia wdmuchiwania proszków do ciekłego metalu jest znana od kilkudziesięciu lat i z powodzeniem stosowana w różnorodnych procesach metalurgicznych i odlewniczych. Zdecydowanie najczęściej stosowane jest rozwiązanie z użyciem lancy zanurzonej pod lustro obrabianego stopu, jako łatwiejsze choć nie pozbawione wielu istotnych wad. W pracy zaprezentowano zakończone kompleksowe badania autorów nad procesem wdmuchiwania proszków bez zanurzania lancy w kąpieli. Przedstawiono nowe spojrzenie na tzw. „kąt stożka rozejścia strumienia” i jego wpływ na skuteczność procesu, przeanalizowano zagadnienie tzw. „skutecznego promienia strumienia” proponowanego przez wcześniejszych badaczy oraz opisano wyniki badań symulacyjnych oraz eksperymentów wdmuchiwania, zarejestrowanych z użyciem kamery do szybkich zdjęć. Podjęto się także ostatecznego porównania rozwiązań lancy zwykłej i opracowanej przez autorów tzw. „lancy kołnierzowej” wskazując na zalety tej drugiej, jako narzędzia do obróbki niewielkich objętości ciekłych stopów np. w procesach wprowadzania żelazostopów czy też modyfikacji.

2

Powder pneumatic injection as a tool for wastes utilization

Jezierski J., Janerka K.

Archives of Materials Science and Engineering

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2009

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Vol. 36, nr 2

118-124

EN

Purpose: Metallurgical process generates many solid, gaseous and liquid wastes. Nowadays when environmental protection is one of the most important problems and when pollution limits are very tight as well, problem of the metallurgical wastes is a strategic one. Design/methodology/approach: In present days the metallurgical and foundry plant have to utilize their own wastes, especially these which are the most dangerous and toxic or have to render harm of its and transfer to another industry branch for further utilization. Nowadays the issue of wastes management has the place both in industrial practice and scientific field too. The presented work is a result of such an approach, where a cooperation between scientific and industrial partners gives good economical and ecological results. Findings: One of the very efficient method of utilization of furnace dusts from any melting furnace or the finest fractions of charging materials is pneumatic powder injection directly into molten metal bath.The method is pretty easy and cost effective in various conditions and its flexibility allows to implement it in almost every foundry or metallurgical plant. Research limitations/implications: Further experiments should be carried out to solve some additional problems appearing during powder injection processes to make them more efficient in various technological conditions. Practical implications: Nowadays in Poland operate more than ten industrial stands for powdered carburizers injection, installation of furnace dust injection back to the melting furnace or pneumatic inoculation of alloys (mostly in cast iron foundries). Originality/value: The paper presents a few modern solutions for recycling and utilization of furnace dusts (in cupolas and EAF’s) and pneumatic carburization with use of powdered carburizers which are very often in form of grinded graphite electrodes wastes. All of the mentioned results and method had been developed in Department of Foundry and some of the designs had been previously patented.

3

Carburization process rate in production of synthetic cast iron

Janerka K., Bartocha D., Szajnar J.

Archives of Materials Science and Engineering

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2009

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Vol. 36, nr 1

55-61

EN

Purpose: The main goal of the paper was to determine the possibility of synthetic cast iron production on base of steel and process scraps as well as the carburization effectiveness, realized with three methods - fully described in main text. Design/methodology/approach: Each of described methods has undoubted advantages but also has a number of disadvantages. In foundry engineering practice the most essential parameters of this process are to obtain as high as possible degree of carbon assimilation from carburizer, in as short as possible time, with high process repeatability. Findings: Decrease of share or elimination the whole amount of the pig iron from charge materials causes reduction cost of gray or ductile cast irons melt. Now the very important issue is working out the effective and, repeatable in industrial conditions, carburization method. Research limitations/implications: Obtained results of experiment on carburization in electric arc furnaces allow to apply pneumatic carburization method in a dozen of domestic foundries. Described in main text researches concern inductive furnaces, which are the wideness group of melting furnaces applied in foundry engineering. Basis on results of these research authors have affirmed that the method characterized with the most carburization effectiveness is the pneumatic injection of carburizer in stream of carrying gas. Practical implications: Industrial application of pneumatic carburization method unfortunately required significant financial outlay on devices purchase. Considerably cheaper method, but characterized with less repeatability is an addition of carburizer to solid charge. Originality/value: Realized experiment is a part of statutory researches, which are carried out in Foundry Department of Institute of Engineering Materials and Biomaterials and supply us with not only utilitarian value - worked out effective method for carburization in industrial conditions, but also experience value - rate change of carbon content increase in function of time for changeable parameters of liquid metal.

4

Influence of binder composition on structure and properties of carbide alloyed composite manufactured with the PIM method

Matula G.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 30, nr 2

193-196

EN

Purpose: Influence of binder composition, debinding and sintering conditions on structure and some selected properties of the M2 type injected high speed-steel with 10% of carbides are demonstrated in the paper. Design/methodology/approach: Torque-load test, rheological tests, microstructure examination, density examination. Findings: Examination of the effect of the binder type and portion on structure and properties of the experimental tool materials with the cermets structure revealed that using the stearic acid not only reduces viscosity, thus improving technological properties of the feedstock, but also extend range of the optimum sintering temperature of the investigated cermets ensuring high density and homogeneous structure. Increasing of sintering temperature increase the density of sintering samples. Practical implications: It is expected that further investigations of these materials will make possible their injection moulding, as well as their heat treatment increasing hardness and strength of matrix and thereby of the whole tool material. The Powder Injection Moulding gives the possibility to manufacturing tools materials on the basis of high speed-steel which characterised very good properties with their final or near net shape. Originality/value: In the paper the using injection of the polymer-powder mix gives the possibility to fabricate carbide alloyed composite which, with their structure and mechanical properties, fill the gap in tool materials between the high-speed steels and cemented carbides.

5

Character of diphase stream force in powder injection technique

Jezierski J., Szajnar J.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

455-458

EN

Purpose: The method of pneumatic injection of powdered reagents into liquid alloys in some moment of melting process is known since many years. Mostly it is carrying out with use of submerged lance but in some cases that technique is difficult or impossible at all to use. This is the reason for making investigations in the filed of powders injection with non-submerged lance. Design/methodology/approach: The main experimental method was measurement and recording of time-changing diphase stream force value with use of dedicated laboratory stand. The recorded data made possible to show character of force in form of graphs and calulation of stream parameters. The last step was formulating of statistical equations joining all important parameters of the process. Findings: In the course of the work was found a diphase stream force character (especially interesting are start and end point of injection). The influence of main pneumatic parameters on the force value was analyzed too. Research limitations/implications: The future experiments will be conducted with use to Fluent 6.2 program for checking the results in computer simulations. The limitation is number of values being analyzed in experimental plan. Practical implications: The invented lance can be used for powders pneumatic injection but only for small its quantities (e.g. microalloying) because non-immersed lance should be used with low stream concentration. The usage of that lance can increase liquid alloy heat losses (not introducing carrier gas into liquid) and lance consumption (non-immersed in liquid bath). Originality/value: The problem of stream force in powder injection process is in Poland only analyzed by Department of Foundry and nobody (in author's opinion) was analyzed it with connection in powder injection. Originality of the researches is a computer recording and analyzing of the diphase stream force. The results should interest every who wants to learn more about pneumatic powder injection.

6

Relationship between stream forces and parameters of the powder injection into metal bath

Jezierski J., Szajnar J.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 4

238-245

EN

Purpose: The pneumatic method of introduction of various powders into ladle or metallurgical furnaces is use because of its many advantages. There are no problems with use of injection lances in electric arc furnaces but in inductive furnaces or ladles, especially big ones the problem of metal flowing out of it may appear. This is the reason why the authors have maiden some experiments which results are presented in the article. Design/methodology/approach: The new lance with a flange was invented and used in powdered material injections experiments. The experimental plan was prepared that contain the most important parameters of pneumatic process. A statistical analysis was made to connect the results of the injection process with its parameters. Findings: The main conclusion is the influence of carrier gas pressure, lance inside diameter and mass concentration of diphase stream on the obtained results. The next one is that changing of the lance geometry could effectively improve the technological parameters of the process and that the new design of the injection lance is prepared properly. Research limitations/implications: The limitations of the results is that the experiments were only the "cold model" ones, without presence of molten metal. The only liquid medium used was water for experiments with stream distance measurement. The nest experiments are planned with injection of powder into laboratory induction furnaces for checking the obtained results. Practical implications: According to the authors, the new lance can be used for introducing a small quantity of the powdered material like modifiers or something like that. Originality/value: The approach to the problem of diphase stream forces and distance of stream in liquid is according to authors' knowledge a new one. The lance with flange proposed for those usage is not present in literature and is an originality too. The paper could be interesting for all interested in problems of melting processes improving.

7

The carburization process rates in synthetic cast iron production

Janerka K., Bartocha D., Szajnar J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

379--382

EN

Purpose: The aim of presented researches was determination of possibility of synthetic cast iron production on base of steel and process scrap as well as determination of carburization effectiveness, realized with three methods: addition of carburizer to charge in solid, addition of carburizer on surface of liquid metal, pneumatic injection of carburizer in stream of carrying gas to liquid metal. Design/methodology/approach: Each of these methods have a undoubted advantages but also have a numer of disadvantages. In foundry engineering practice the most essential parameters of this process are to obtain as high as possible degree of carbon assimilation from carburizer, in as short as possible time, with high proces repeatability. Findings: Decrease of share or elimination of the pig iron from charge materials causes significant reduction of cast iron melt costs. Working out the effective and repeatable crburization method is a very important issue. Research limitations/implications: The result of carburization in arc electric furnaces experiments carried out by the authors of this paper made possibility on application method of pneumatic carburization in a dozen of domestic foundries. Presented below researches concern inductive furnaces, which are a wide group of melting furnaces applied in foundry engineering. Basis on these researches affirmed that the most effectiveness carburization method is the pneumatic injection of carburizer in stream of carrying gas. Practical implications: This method required significant financial outlay on devices purchase. Considerably cheaper method, but less repeatable is a addition of carburizer to solid charge. Originality/value: Realized experiments are a part of statutory researches and have not only utilitarian value (worked out effective method for carburization in industrial conditions), but also experience (rate change of carbon content increase in function of time for changeable parameters of liquid metal.

8

Method and new lance for powder injection into liquid alloys

Jezierski J., Szajnar J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

349--352

EN

Purpose: The pneumatic powder injection into liquid alloys is known since many years. It is use in many metallurgical processes (recarburization, alloy additions introduction, desulphurization etc.). The problem in some cases is to prevent the carrier gas introduction into liquid bath. Design/methodology/approach: The objectives were achieved by researches with laboratory injection stand. The main research method was measurement of stream parameters and computation of pneumatic injection indexes. Findings: The new injection lance was invented and analyzed and this is one of the main subjects of this paper. The lance has a construction, that makes possible even complete elimination of carrier gas introduction into liquid metal with proper particles stream range. The paper shows the results of the tests of lances with various geometrical parameters and model experiments with diphase stream force measurement. Research limitations/implications: The future research should be made with various type of powdered materials to find the question what are the limits of changing the most important parameters (grain size, stream concentration etc.). The limitation is number of values being analyzed (in powder injection processes there are many) in experimental plan. Practical implications: The lance can be used for powders pneumatic injection but only for small its quantities (e.g. microalloying) because non-immersed lance should be used with low stream concentration. The usage of that lance can decrease liquid alloy heat losses (not introducing carrier gas into liquid) and lance consumption (non-immersed in liquid bath). Originality/value: The original value of the paper is taking into account the parameter called by authors “diphase stream force” on liquid metal surface being “attacked” by particles (or carrier gas stream). Nobody (in author’s opinion) was analyzed that problem with connection in powder injection processes. The paper can be helpful for everybody who is studying pneumatic injection processes.

9

Wdmuchiwanie proszków do ciekłych stopów metali jako narzędzie poprawy ich jakości

Jezierski J., Janerka K., Szajnar J.

Archiwum Odlewnictwa

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2006

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R. 6, nr 18/1

535--540

PL

W pracy przedstawione zostały korzyści wynikające z zastosowania metody pneumatycznego wprowadzania sproszkowanych reagentów do ciekłych stopów żelaza w aspekcie poprawy ich jakości. Najszersze zastosowanie wdmuchiwania proszków w odlewnictwie wiąże się z nawęglaniem (dowęglaniem) ciekłego żeliwa a także wprowadzaniem niewielkich ilości dodatków stopowych i analiza tych właśnie zagadnień jest głównym tematem niniejszej pracy. Ponadto przedstawiono propozycję modyfikacji stanowiska do wdmuchiwania proszków, zapewniającą utrzymanie wysokich wartości wskaźników technologicznych (efektywności) przy jednoczesnej poprawie jakości ciekłego stopu w czasie procesu wdmuchiwania.

EN

In the paper has been presented the benefits of pneumatic reagents introduction into liquid alloys in aspect of its quality improving. The widest use of powder injection technique in foundry is the cast iron recarburization and small quantities of alloy additions introduction and those problems are the main subject of this work. Moreover, there were presented a modification of injection stand which give the same high technological parameters (efficiency) and better quality of alloy through all the injection process.

10

Metoda wdmuchiwania proszków do ciekłych stopów jako narzędzie poprawy jakości i ekonomiczności produkcji odlewniczej

Gawroński J., Jezierski J., Janerka K.

Archiwum Odlewnictwa

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2004

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R. 4, nr 12

67--72

PL

W pracy przedstawiono korzyści wynikające z pneumatycznego wprowadzania reagentów (nawęglaczy, dodatków stopowych) do ciekłego stopu w aspekcie ekonomiczności procesu metalurgicznego oraz jakości uzyskiwanych tworzyw odlewniczych. Wskazano na zalety związane z wdmuchiwaniem materiałów ziarnistych jak również na wady i niebezpieczeństwa tego rodzaju obróbki wynikające ze specyfiki niektórych operacji metalurgicznych, prowadzonych w różnych jednostkach piecowych.

EN

In the paper has been presented the benefits of pneumatic reagents introduction (carburizers, alloy additions) into liquid alloy in aspect of profitability of castings production and quality of the made materials. There have been shown the advantages of grain materials blowing in but the disadvantages and risks of its, caused various furnaces usage for various metallurgical process too.

11

Wpływ prędkości ziaren żelazostopów na wskaźniki pneumatycznego wprowadzania dodatków stopowych do ciekłego żeliwa

Jezierski J.

Archiwum Odlewnictwa

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2003

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R. 3, nr 10

307--314

PL

W artykule przedstawiono wyniki eksperymentów wprowadzania dodatków stopowych do ciekłego żeliwa. Na uzyskiwane wskaźniki technologiczne tego procesu wpływ ma szereg parametrów takich jak konstrukcja podajnika i lancy wdmuchującej, wielkość wprowadzanych ziaren, temperatura ciekłego metalu i inne. Jednak na podstawie badań stwierdzono, że najważniejszy wpływ na efektywność wdmuchiwania dodatków stopowych do ciekłego żeliwa lancą niezanurzoną ma prędkość ziaren żelazostopów na wylocie z lancy. Zapewnia ona wystarczający dla należytego rozprowadzenia dodatku stopowego zasięg strumienia dwufazowego w ciekłym stopie.

EN

In the paper has been presented the results of the experiments of alloy addition introduction into liquid cast iron. There are many parameters that influence on the technological parameters of the process as: powder dispenser and a lance construction, size of the introduced particles, liquid metal bath temperature and others. There were assumed that the main influence on the efficiency of alloy additions injection into liquid cast iron with use of non-submerged lance has the velocity of ferroalloy grains in lance outlet. It ensures the proper diphase stream range for appropriate distribution of alloy addition in liquid alloy.

12

Pneumatyczne wprowadzanie FeCr do ciekłego żeliwa

Jezierski J., Jura S., Janerka K.

Archiwum Odlewnictwa

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2001

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R. 1, nr 2

161--166

PL

W artykule przedstawiono wyniki eksperymentów wprowadzania dodatków stopowych metodą pneumatyczną przy zastosowaniu lancy nie zanurzonej. Prowadzone eksperymenty mają w założeniu wyjaśnić niektóre aspekty dynamiki strumienia dwufazowego, mającej zasadniczy wpływ na wyniki procesu. Przeanalizowano głównie wpływ wielkości ziarna wdmuchiwanego żelazostopu na efektywność przyswajania chromu przez ciekłe żeliwo. Zastosowania lancy nie zanurzonej wymaga specyfika pieców indukcyjnych.

EN

This paper presents results of pneumatic injection of alloy additions using non-immersed lance. The experiments should explain some aspects of diphase stream dynamics, which fundamentally influences on the results of the process. Influence of injected ferroalloys grain size for increasing of chromium contents was analyzed. Experiments were concern for a case of injection into an induction furnace with non-submerged lance (above the liquid) powder injection into liquid cast iron.

13

Modelowanie fizyczne procesu wdmuchiwania proszków do ciekłego metalu

Janerka K., Gawroński J., Cholewa M., Szajnar J., Szlumczyk H., Jezierski J.

Krzepnięcie Metali i Stopów

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1999

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R. 1, nr 40

133--140

PL

Wdmuchiwanie sproszkowanych materiałów do ciekłego metalu jest metodą pozwalającą na intensyfikację prowadzonego procesu metalurgicznego (nawęglanie, wprowadzanie dodatków stopowych, cząstek dyspersyjnych w celu otrzymania kompozytu). Bardzo ważnym zagadnieniem jest poznanie oddziaływania strumienia dwufazowego w ciekłym metalu. Szczególnie istotne znaczenie ma głębokość przenikania strumienia w zależności od sposobu wprowadzenia lancy oraz natężenia przepływu gazu i materiału. Jedyną drogą umożliwiającą określenie tych parametrów jest przeprowadzenie badań modelowych. Stąd w pracy przedstawiono zagadnienia modelowania fizycznego wdmuchiwania cząstek o różnej gęstości, położeniu lancy i zmiennych parametrach strumienia dwufazowego do wody. Stanowią one podstawę do określenia optymalnych parametrów wdmuchiwania cząstek zbrojących do osnowy kompozytu wytwarzanego na bazie stopów aluminium.

EN

Injecting of powdered materials into the liquid is a method making possible to intensify the metallurgical process (recarburization, making additions, dispergated particles in order to obtain composites). The issue of the great concern is to learn the effect of the two-phase stream in liquid metal. The matter of the greatest significance is the depth of the stream penetration according to the method of the lance inersion as well as gas and material rate of flow. The only one way making possible to determine those parameters is to carr out the model testing. Thereby, the work presents issues concerning modelling of a physical injection of particles having different densities, at various position of the lance as well as variable parameters of the two-phase stream into water. Obtained results were presented in the form of photographs. They form grounds for optimal parameters determination for reinforcing particles injection to the matrix of the composite produced from aluminum alloys.